How to update without wireless

Actually he can,just ask a friend to hotspot(with an android device because iphone to iphone hotspot work different and dont allows update,but android is recognized like a router for iphone and allow update)and its not necessary its plugged in to power,for update battery percentage required its 50% or superior,so fill it up at 100% ask your friend with an android device to hotspot you and lets go

have a great day 

You don't, sorry.

To perform an update procedure wirelessly, you need to connect your device to a reliable and fast Wifi Network with internet access (no cellular data, unless you use a 5G network, no personal hotspot, no VPN connections, no low power mode are admitted). AND your iPhone should be plugged into power during the whole update process.

If you don't have a wifi network, "borrow" one from your friends/neighbors, or ask for help at an Apple Store or Authorized Service Provider or Authorized Reseller.

Do not forget to create a full backup of your device, before any updates.

Regards

Giulio